Cable size?

[jock mcsporran]

Question for any electricians.
I'm building a garage just now to replace a shed. The previous owner had run a 2.5mm armoured cable but I feel it's too small so plan on replacing it with a larger one.
I want to be able to use a Mig welder (smallish), compressor plus usual garage tools.
Would a single 10mm be better or maybe 2 x 6mm? It a 50m run from the house CU to the garage.

[Neil - YVM]

For 3kw, 2.5mm SWA is ok.

Work out the maximum likely load, then use the volt drop calculator in the link to determine the cable size required.

http://www.tlc-direct.co.uk/Technical/Charts/Volta...

[jock mcsporran]

The welder would peak at over 3kw. Add on anything else and I'd rather over spec than under spec.

[R1 Indy]

10mm SWA would be complete overkill for a garage.

2.5mm at that distance would be fine for a 20A breaker, which should be fine for general tools etc.

Or possibly 4mm if you want up to 40A.

XLPE SWA has far better current ratings that standard PVC twin/earth.

[ch427]

If it were me id put a 6mm in, maybe a bit overkill but plenty of capacity for future expansion if needed.

[eliot]

ch427 said:

If it were me id put a 6mm in, maybe a bit overkill but plenty of capacity for future expansion if needed.

I agree.
But FWIW i ran 10mm into my old shed, but it was running my tig which pulls in excess of 50amps ac when welding ally at 200amps welding current.

[jock mcsporran]

Cheers. I'd want to keep some spare capacity to potentially install a scissor lift at some point. These seem to run between 3-4kw. Appreciate I wouldn't have everything on at the same time though.

[jock mcsporran]

Cheers. I'd want to keep some spare capacity to potentially install a scissor lift at some point. These seem to run between 3-4kw. Appreciate I wouldn't have everything on at the same time though.